Pavement friction under wet conditions is a critical factor affecting driving safety and is determined significantly by water-film thickness (WFT). Although current road geometric design standards incorporate wet-pavement friction coefficients as design parameters, they do not adequately account for the effects of WFT. This study estimates the variation in the coefficient of friction caused by changes in the WFT and applies the results to the calculation of stopping sight distance (SSD) and radius of curvature (RC), which are essential elements in road geometry design. Through this approach, the study identifies the limitations of current standards and proposes potential improvements. WFT was estimated using the Gallaway model, which was previously verified through comparative analysis and experimental validation. The model incorporates key influencing factors such as rainfall intensity, pavement slope, drainage path length, and mean texture depth. Based on the estimated WFT, the longitudinal and lateral friction coefficients were calculated using Gallaway’s SN and Lamm’s models, respectively. Using these friction values, the SSD and RC were evaluated under various pavement and environmental conditions. Furthermore, comparisons with existing design guidelines were performed to assess whether the predicted values satisfy the standards under different conditions. Additionally, areas requiring improvement were identified. The analysis confirmed that WFT increases with rainfall intensity and drainage path length, whereas it decreases as the pavement slope, mean texture depth, and tread depth increase. An increase in the WFT significantly reduces the friction coefficient, which consequently increases the SSD and required RC. In particular, under conditions such as heavy rainfall, worn treads, long drainage paths, and shallow surface textures, the calculated SSD and RC typically exceed the minimum requirements of current road-design standards. By contrast, ensuring sufficient surface texture effectively maintains friction performance and mitigates increases in the SSD and RC. The findings of this study suggest that current road-design standards—based on dry or vaguely defined wet conditions—may not sufficiently address the effects of WFT on pavement friction. A quantitative, WFT-based approach is required for more realistic friction estimations. To enhance safety in rainy conditions, road designs should incorporate structural and material improvements, such as optimizing pavement slopes, reducing the drainage path length, maintaining adequate surface texture and tread depth, and adopting high-performance surfacing materials. Additionally, dynamic speed-management systems during rainfall and preventive maintenance for sections with inferior drainage should be considered to improve driving safety under wet weather conditions.

Purpose: This study was to analyze refractive error and corneal curvature radius in childhood myopia. Methods: The average age of 9.92 ± 1.08 years Children 50 people(24 males and 26 females) were evaluated for refractive error with an automatic refractometer, Pentacam was used to measure the corneal curvature radius. Results: The mean total spherical diopter was -2.43 ± 1.39D and astigmatism diopter was -0.75 ± 0.66D, horizontal radius of curvature was 7.88 ± 0.23mm, vertical radius of curvature was 7.67 ± 0.23mm, corneal astigmatism -1.18 ± 0.56D, diameter was 11.75 ± 0.47mm, eccentricity was 0.55 ± 0.10. There was no significant difference spherical diopter(t=-0.357, p=0.722), corneal astigmatism (t=1.410, p=0.162), eccentricity(t=0.627, p=0.532) in male and female, astigmatic diopter(t=2.097, p=0.039), horizontal radius of curvature(t=2.397, p=0.018), vertical radius of curvature(t=2.685, p=0.009), diameter(t=2.157, p=0.033) were significantly different. There was no significant difference spherical diopter(t=-0.952, p=0.343), astigmatism diopter(t=1.260, p=0.211), horizontal radius of curvature (t=-0.596, p=0.553) vertical radius of curvature(t=-0.495, p=0.621), corneal astigmatism(t=0.662, p=0.509), diameter (t=-0.411, p=0.682), eccentricity (t=0.080, p=0.937) between in male and female. Conclusions: Male and female were significant different astigmatism diopter, horizontal radius of curvature, vertical radius of curvature, diameter in childhood myopia. There was no significant difference between right eye and left eye.

To evaluate the possibility of negative reaction at seismic isolation bearings subject to seismic load, seismic records of El-Centro and artificial earthquake wave were applied to a single-plate girder bridge with various analytical parameters of curvature radii and skew angles. It is found that seismic analysis using those parameters should be carried out to prevent negative reaction at support.

Curved girders show very complex behavior compare to straight girders because the torsional moments always act on the structure even if there are no additional loads except self-weight. For this reason, engineers need to consider torsional behavior when design or analyse structure. However, most of curved bridges are designed as a series of straight girders because design specification does not reflect the curved beam theory. In this paper, curved girders are analysed by FEA program and the results are compared with the results of straight girders. Selecting the radius of curvature as a parameter, suitable analysis method for design of horizontally curved girder was suggested.